The film beat out Anomalisa, The Good Dinosaur, Inside Out, The Peanuts Movie and Shaun the Sheep Movie to win the award.
The movie, about the inner workings of a young girl's emotions, marks Pixar Studio's seventh Golden Globe win for best animated feature since the category was created a decade ago.
Co-writer and co-director Pete Docter accepted the award with producer Jonas Rivera. "We felt like growing up is really hard," said Docter in his acceptance speech. "And that was an interesting thing to make a movie about."